<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width:300px;
            height:300px;
            background-color:red;
        }
    </style>
</head>
<body>
    <div class="box"></div>
    <script>
        const oBox=document.querySelector(".box");
        function center(e) {
            console.log("center");
            console.log(e);
            console.log(this);
        }
        oBox.onmousemove=throttle(center,300);
        function throttle(fn,time) {
            let lastTime=0;
            return function(e){
                let nowTime=Date.now();
                //书写一个看门狗
                if(nowTime-lastTime<time) {
                    return;
                }
                lastTime=nowTime;
                center.call(this,e);

            }
        }
    </script>
    
</body>
</html>